Answer:
=3x^5−53x^3−20x^2−10x−40
Step-By-Step explanation:
=(3x^4+−12x^3+−5x^2+−18+8)(x+4)
=(3x^4)(x)+(3x^4)(4)+(−12x^3)(x)+(−12x^3)(4)+(−5x^2)(x)+(−5x^2)(4)+(−18)(x)+(−18)(4)+(8)(x)+(8)(4)
=3x^5+12x^4−12x^4−48x^3−5x^3−20x^2−18x−72+8x+32
=3x^5−53x^3−20x^2−10x−40
